This invention relates to a method for processing a light-sensitive silver halide color photographic material, more particularly to a method for processing a light-sensitive silver halide color photographic material which is capable of performing processing rapidly and improved in bleaching fog and also improved in fixability.
Processing of light-sensitive material comprises basically two steps of color developing and desilverization, and desilverization comprises the steps of bleaching and fixing or the bleach-fixing step. In addition to the above steps, the rinsing step, the stabilizing step, etc. are added as additional steps.
For the processing solution having bleaching ability to be used in the desilverization step of light-sensitive material, as the oxidizing agent for bleaching the image silver, inorganic oxidizing agents such as potassium ferricyanide, dichromic acid salt, etc. have been widely used.
However, for the processing solution having bleaching ability containing these inorganic oxidizing agents, some vital defects have been pointed out. For example, although potassium ferricyanide and dichromic acid salt are relatively excellent in bleaching power of image silver, there is fear that they may be decomposed by light to generate cyan ions or hexavalent chromium ions harmful to human bodies, thus having undesirable properties in view of prevention of pollution. Further, the processing solution containing these inorganic oxidizing agents have the drawback that it is difficult to regenerate these agents for use without discarding the waste liquor after processing.
In contrast, as one suited for such requirements such as rapid processing, simplification and regeneration availability of waste liquor, etc. without little problem in pollution, processing liquors with the use of a metal complex of an organic acid such as aminopolycarboxylic acid metal complex, etc. as the oxidizing agent are now becoming to be used. However, the processing solution by use of a metal complex of an organic acid is slow in oxidizing power, and therefore has the drawback that the bleaching speed (oxidation speed) of the image silver (metallic silver) formed during the developing step is slow. For example, iron (III) ethylenediaminetetra acetic acid which is considered to have strong bleaching power among aminoplycarboxcylic acid metal complexes has been partially applied practically as the bleaching solution and bleach-fixing solution, but it is deficient in bleaching power in a high sensitivity light-sensitive silver halide color photographic material comprising primarily silver bromide or silver iodobromide emulsion, particularly in color paper for photographing and color negative film, color reversal film for photographing, which contains silver iodide as silver halide and has a high silver content, and therefore has a drawback that a long time is required for the bleaching step.
On the other hand, in the developing processing method, wherein a large amount of light-sensitive silver halide photographic materials are continuously processed by means of an automatic developing machine, etc., for avoiding worsening of performance of the bleaching solution due to change in concentrations of components, a means for maintaining the components of the processing solution at constant levels is required. As such means, in recent years, from the standpoints in economy and pollution, there have been proposed the so-called concentrated low replenishing system which replenish a small amount of these replenishing solutions concentrated, or alternatively the method in which a regenerant agent is added to the overflowed solution, which is then used again as the replenishing solution.
Particularly, in the bleaching solution, there has been practically applied the method in which an organic acid ferrous complex, for example, iron (II) complex of ethylenediaminetetraacetic acid is returned by aeration to iron (III) complex of ethylenediaminetetraacetic acid, namely oxidized to organic acid ferric complex, and further a regenerant is added to replenish deficient components to be used again as the replenishing solution.
However, in recent years, for short time processing of light-sensitive silver halide photographic materials, and reduction in collection and delivery cost, the so called compact laboratory (also called mini-laboratory) is coming to the forefront, and in such laboratory, simplification of processing and reduction in installation area of developing machine are highly demanded, and therefore regeneration processing requiring cumbersome labors and management, and also processing space is not desirable.
Accordingly, the concentrated low replenishing system which performs low replenishment without performing regeneration processing is preferred. However, if the amount of the bleaching solution replenished is extremely reduced, the concentration of the color developer carried over into the bleaching solution will be elevated, and also is susceptible to concentration by evaporation, whereby accumulation of the color developer components is further increased. Thus, if the concentrations of the color developer components are increased, the ratio of the color developing agent, the sulfite, etc., which are reducing components, attached and mixed into the light-sensitive material will be enhanced to inhibit the bleaching reaction, whereby there occur problems of silver retention and the so-called leuco dye formation of cyan dye. Further, as a serious problem, there occurs liability to generation of bleaching fog.
This bleaching fog is particularly stressed in low replenishment of the bleaching solution in recent years.
In recent years, the techniques employing propylenediaminetetraacetic acid ferric complex as a novel bleaching agent have been known in Japanese Unexamined Patent Publications Nos. 65441/1988, 141056/1988 and 139348/1988. However, propylenediaminetetraacetic acid ferric complex, although extremely excellent in silver bleaching ability, has been found to have several drawbacks. One is that the ferrous complex formed by the bleaching reaction of silver and the reducing components carried over with the light-sensitive material, etc. as described above can be oxidized with difficulty. For this reason, the ferrous complex formed may be accumulate in the bleaching solution to make leuco formation of the dye or generate silver retention. Also, another defect is that due to its strong oxidizing power, the color developing agent is oxidized therewith during the bleaching step, whereby indiscriminate coupling reactions may occur, thereby giving rise to the so-called bleaching fog. Further, it has been also found that, as the light-sensitive color photographic material is processed, fixability tends to deteriorate to great extent as compared with the case when ethylenediaminetetraacetic acid ferric complex of the prior art is used as the bleaching agent, which tendency will appear remarkably particularly when the amount of processing is small.